TaskTracker will tell JobTracker how many free slots it has through
heartbeat. And JobTracker will choose the best tasktracker with the
consideration of data locality.
On Thu, Oct 28, 2010 at 2:52 PM, Zhenhua Guo wrote:
> Hi, all
> I wonder how Hadoop schedules mappers and reducers (e.g. consider
> load balancing, affinity to data?). For example, how to decide on
> which nodes mappers and reducers are to be executed and when.
> Thanks!
>
> Gerald
>
--
Best Regards
Jeff Zhang